An open access study, published March 27 in the Journal of NeuroEngineering and Rehabilitation, that evaluated the impact of sensory feedback on prosthesis control found that the feedback was beneficial only when users were performing complex tasks.
The researchers evaluated the impact of factors such as task complexity and user learning in a longitudinal assessment of six subjects with amputation, using a clinical setup (socket, embedded control) and a range of tasks (box and blocks, block turn, and clothespin and cups relocation). For the sensory feedback, the subjects wore a bracelet with four by two uniformly placed vibro-tactors providing information on contact, prosthesis state (active function), and grasping force. The subjects also completed a questionnaire for the subjective evaluation of the feedback.
According to the study’s authors, the tests demonstrated that feedback was beneficial only in the complex tasks (block turn, and clothespin and cups relocation), and that training had an important, task-dependent impact. In the clothespin relocation and block turn tasks, training allowed the subjects to establish successful feedforward (motor) control, which made the sensory feedback redundant. In the cups relocation task, however, the subjects needed some training to learn how to properly exploit the feedback. The subjective evaluation of the feedback was consistently positive, the researchers concluded, regardless of the objective benefits.
